linux-toradex.git/include/net/inetpeer.h, branch v2.6.36.4

inetpeer: restore small inet_peer structures

2010-06-16T18:55:39+00:00

Addition of rcu_head to struct inet_peer added 16bytes on 64bit arches.

Thats a bit unfortunate, since old size was exactly 64 bytes.

This can be solved, using an union between this rcu_head an four fields,
that are normally used only when a refcount is taken on inet_peer.
rcu_head is used only when refcnt=-1, right before structure freeing.

Add a inet_peer_refcheck() function to check this assertion for a while.

We can bring back SLAB_HWCACHE_ALIGN qualifier in kmem cache creation.

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

inetpeer: RCU conversion

2010-06-15T21:23:38+00:00

inetpeer currently uses an AVL tree protected by an rwlock.

It's possible to make most lookups use RCU

1) Add a struct rcu_head to struct inet_peer

2) add a lookup_rcu_bh() helper to perform lockless and opportunistic
lookup. This is a normal function, not a macro like lookup().

3) Add a limit to number of links followed by lookup_rcu_bh(). This is
needed in case we fall in a loop.

4) add an smp_wmb() in link_to_pool() right before node insert.

5) make unlink_from_pool() use atomic_cmpxchg() to make sure it can take
last reference to an inet_peer, since lockless readers could increase
refcount, even while we hold peers.lock.

6) Delay struct inet_peer freeing after rcu grace period so that
lookup_rcu_bh() cannot crash.

7) inet_getpeer() first attempts lockless lookup.
   Note this lookup can fail even if target is in AVL tree, but a
concurrent writer can let tree in a non correct form.
   If this attemps fails, lock is taken a regular lookup is performed
again.

8) convert peers.lock from rwlock to a spinlock

9) Remove SLAB_HWCACHE_ALIGN when peer_cachep is created, because
rcu_head adds 16 bytes on 64bit arches, doubling effective size (64 ->
128 bytes)
In a future patch, this is probably possible to revert this part, if rcu
field is put in an union to share space with rid, ip_id_count, tcp_ts &
tcp_ts_stamp. These fields being manipulated only with refcnt > 0.

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

inetpeer: Optimize inet_getid()

2009-11-14T04:46:58+00:00

While investigating for network latencies, I found inet_getid() was a
contention point for some workloads, as inet_peer_idlock is shared
by all inet_getid() users regardless of peers.

One way to fix this is to make ip_id_count an atomic_t instead
of __u16, and use atomic_add_return().

In order to keep sizeof(struct inet_peer) = 64 on 64bit arches
tcp_ts_stamp is also converted to __u32 instead of "unsigned long".

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

net: cleanup include/net

2009-11-04T13:06:25+00:00

This cleanup patch puts struct/union/enum opening braces,
in first line to ease grep games.

struct something
{

becomes :

struct something {

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

net: remove CVS keywords

2008-06-12T04:00:38+00:00

This patch removes CVS keywords that weren't updated for a long time
from comments.

Signed-off-by: Adrian Bunk 
Signed-off-by: David S. Miller

[INET]: Use list_head-s in inetpeer.c

2007-11-13T05:27:28+00:00

The inetpeer.c tracks the LRU list of inet_perr-s, but makes
it by hands. Use the list_head-s for this.

Signed-off-by: Pavel Emelyanov 
Signed-off-by: David S. Miller

[IPV4] inet_peer: Group together avl_left, avl_right, v4daddr to speedup lookups on some CPUS

2006-10-20T07:28:35+00:00

Lot of routers/embedded devices still use CPUS with 16/32 bytes cache
lines.  (486, Pentium, ...  PIII) It makes sense to group together
fields used at lookup time so they fit in one cache line.  This reduce
cache footprint and speedup lookups.

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

[NET]: reduce sizeof(struct inet_peer), cleanup, change in peer_check_expire()

2006-10-16T06:14:17+00:00

1) shrink struct inet_peer on 64 bits platforms.

[IPV4]: inetpeer annotations

2006-09-29T01:01:09+00:00

This one is interesting - we use net-endian value as search key, but
order the tree by *host-endian* comparisons of keys.  OK since we only
care about lookups.  Annotated inet_getpeer() and friends.

Signed-off-by: Al Viro 
Signed-off-by: David S. Miller

[IPV4]: Safer reassembly

2006-01-03T21:10:31+00:00

Another spin of Herbert Xu's "safer ip reassembly" patch
for 2.6.16.

(The original patch is here:
http://marc.theaimsgroup.com/?l=linux-netdev&m=112281936522415&w=2
and my only contribution is to have tested it.)

This patch (optionally) does additional checks before accepting IP
fragments, which can greatly reduce the possibility of reassembling
fragments which originated from different IP datagrams.

Signed-off-by: Herbert Xu 
Signed-off-by: Arthur Kepner 
Signed-off-by: David S. Miller